Mutual locks, in particular as an accessory, are known for circuit breaker configurations with, for example, two switches arranged next to one another. The interface between the circuit breaker and the lock is in this case often formed by a disk cam/plunger mechanism. The disk cam can be integrated in a drive shaft within the switch; the lock is driven or the switch is prevented from opening via the disk cam. In the process, the plunger enters the circuit breaker and forms the connecting element between the internal disk cam and the external lock.
For mutual locking of the two switches, two plungers are used which are capable of moving in opposition to one another in the longitudinal direction of the plunger via a forced mechanical coupling. When a circuit breaker opens, the plunger thereof is pushed by the disk cam out of its zero position into its opening position out of the circuit breaker. At the same time, the other plunger is pushed out of its zero position into the other circuit breaker by the forced coupling, i.e. is shifted into its locking position. When the plunger has reached the locking position, the associated circuit breaker is blocked and it is therefore no longer possible for the circuit breaker to open.
It is necessary for correct operation for the contact faces of the disk cam and the plunger to each be located at precisely predetermined positions. A deviation from this is only possible within tight tolerance ranges, which results in considerable sensitivity to manufacturing tolerances and wear. In order to make an adjustment, the positions of the disk cam and the plunger each need to be readjusted.